1. Field of the Invention
The present invention relates to spinning manifolds used in melt-spinning installations for synthetic high molecular weight polymers. Such manifolds have an elongated hollow member containing cavities for the conduction of a heating medium and at least one vertical nozzle shaft with heatable walls. In addition, a plurality of separately dismountable nozzle blocks having rectangular cross-sections are serially arranged within the nozzle shaft.
2. Background of the Invention
In the spinning manifolds known in the prior art, the nozzle blocks are part of a spinning block or unit. The spinning block comprises a spinning pump, driving shaft, pump block or unit, nozzle block and insulating or filler elements. The nozzle block comprises a nozzle block housing having a filter, a supporting plate and a nozzle plate in which separate capillaries for the spinning of high polymer filaments are arranged. The nozzle blocks may be fitted into the nozzle shaft from below or from above. The basic construction of such a spinning block is adequately described in West German Patent Application No. 23 31 764.
A prerequisite to the production of quality filaments is that the processing parameters for the areas surrounding each separate filament must be as identical as possible. Temperature is especially crucial. Thus, the temperature of the spinning melt and all parts of the spinning block with which the melt comes into contact should be at the same temperature.
Spinning systems which have a plurality of nozzle blocks per nozzle shaft permit the production of several cables of polymer filaments in one spinning operation. Thus spinning systems with a plurality of nozzle blocks present a favorable balance between the requirements of capacity and space. However, the conventional serial arrangement of nozzle blocks places one nozzle block immediately adjacent to another. The consequence of this arrangement is that the nozzle blocks on the ends of a serial arrangement are in heat exchange with three sides of the heated nozzle shaft wall, while the interior nozzle blocks only exchange heat with two sides of the heated nozzle shaft wall.
The heating in spinning manifolds is predominately by heat radiation or exchange. Because the heat flow characteristics of the heating medium differ for the interior nozzle blocks and the exterior nozzle blocks, the temperature of the central nozzle blocks may be as much as 20 degrees centrigrade lower than the temperature of the end nozzle blocks. Thus, the conventional serial arrangement of nozzle blocks in spinning manifolds necessarily means that the processing parameters will vary from one nozzle block to another and that the resulting spun filaments will not be of the highest possible quality.